Essential fatty acids, prostaglandins and heart function

Abstract

Coronary flow (q cor), spontaneous frequency (f) and contractile force (F) of isolated, perfused hearts of rats fed a diet containing mixtures of various fats are positively related to the amount of linoleic acid in the diet. The production of prostacyclin (the main prostaglandin formed in the heart) of isolated, perfused hearts of essential fatty acid deficient rats is about 0.3 ng min −1 g −1 (dry weight), while that of isolated hearts of rats fed a diet with 5 en% sunflowerseed oil (containing 70% 18:2 ( n-6)) is about 4 ng min −1 g −1; this production does not further increase in hearts of rats fed larger amounts of sunflowerseed oil. Feeding rats a diet with 35 en% linseed oil (with 52% 18:3( n-3)) for 8 weeks results in a 50% decrease in prostacyclin production of their isolated hearts, but does not significantly influence q cor, f or F. Intraperitoneal injection of acetylsalicyclic acid (83 μmol kg −1) or indomethacin (28 μmol kg −1) in rats completely inhibits the PGI 2 release from their isolated hearts and decreases q cor and f, but does not influence F. The observed effects on heart function are syntematic but moderate, and may in vivo be surpassed by regulatory influences. They show, however, that dietary essential fatty acids have definite effects on cardiac function which can partly be explained via an influence on prostaglandin synthesis and, for the other part, probably via influences on membrane composition and fluidity. The latter suggestion needs further investigation.